The purpose of this study is to evaluate the short- and long-term somatic and neurobehavioral effects of maternal methadone maintenance during the first 3 years of life. In addition, methadone dispisition during pregnancy and in the newborn is also being investigated. Intake of patients is cleared and a total of 64 children of methadone mothers and 32 control children have been enrolled. In our follow-up we have 59 study (a 23% loss) and 23 matched control children (a 29% loss) with the oldest child being 30 mo. of age. The infants and children are seen every 2 months for the 1st year of life and then every 3 months (evaluations done every 6 months) for well baby checks, neurobehavioral evaluations, immunizations. All emergency medical care is also provided in our clinic. Our preliminary analyses of the data have shown: 1. No difference in growth or development. 2. Neurologically methadone babies up to 8 months of age are different from control in tone but by 12 months, there are no differences. 3. During the first year of life there were no differences in rate of infections but after 12 months a trend of a higher incidence of otitis media and URI's appears in the methadone babies. 4. Bayley mental and motor indeces scores are consistently lower in the methadone babies than control babies after two months and are significantly lower by 12 months of age. No differences were noted in visual habituation.